Thursday, June 17, 2010

What exactly is solar energy ?

Solar power is radiant energy that's produced by the sun. Every single day the sun radiates, or sends out, a huge quantity of energy. The sun radiates more energy in one second than people have used since the beginning of time!

The energy of the Sun derives from within the sun itself. Like other stars, the sun is really a big ball of gases––mostly hydrogen and helium atoms.

The hydrogen atoms in the sun’s core combine to form helium and generate energy in a process called nuclear fusion.

During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. But the helium atom contains less mass than the four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.

It requires countless years for the energy in the sun’s core to make its way to the solar surface, after which somewhat over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth at a speed of 186,000 miles per second, the speed of light.

Only a small portion of the power radiated by the sun into space strikes our planet, one part in two billion. Yet this amount of energy is enormous. On a daily basis enough energy strikes the usa to supply the nation’s energy needs for one and a half years!

Where does all of this energy go?

About 15 percent of the sun’s energy that hits the earth is reflected back to space. Another 30 percent is used to evaporate water, which, lifted into the atmosphere, produces rainfall. Solar energy is also absorbed by plants, the land, and the oceans. The rest could be employed to supply our energy needs.

Who invented solar energy ?

Humans have harnessed solar power for centuries. As early as the 7th century B.C., people used simple magnifying glasses to concentrate the light of the sun into beams so hot they would cause wood to catch fire. More than a century ago in France, a scientist used heat from a solar collector to make steam to drive a steam engine. In the beginning of this century, scientists and engineers began researching ways to use solar energy in earnest. One important development was a remarkably efficient solar boiler introduced by Charles Greeley Abbott, an american astrophysicist, in 1936.

The solar hot water heater gained popularity at this time in Florida, California, and the Southwest. The industry started in the early 1920s and was in full swing prior to The second world war. This growth lasted prior to the mid-1950s when low-cost gas had become the primary fuel for heating American homes.

The public and world governments remained largely indifferent to the possibilities of solar power prior to the oil shortages of the1970s. Today, people use solar technology to heat buildings and water and also to generate electricity.

How we use solar power today ?

Solar power is employed in a number of different ways, of course. There are 2 simple forms of solar energy:

* Solar thermal energy collects the sun's warmth through 1 of 2 means: in water or in an anti-freeze (glycol) mixture.

Let us discuss the five most practical and popular techniques solar power can be used:

1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden tools. Portable units can be utilized for everything from RV appliances while single panel systems can be used traffic signs and remote monitoring stations.

2. Solar pool heating. Running water in direct circulation systems via a solar collector is a very practical solution to heat water for your pool or hot tub.

3. Thermal glycol energy to heat water. In this method (indirect circulation), glycol is heated by sunshine and the heat is then transferred to water in a warm water tank. This technique of collecting the sun's energy is more practical now than ever before. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in 3 years or less.

4. Integrating solar photovoltaic energy into your home or business power. In many parts of the world, solar photovoltaics is an economically feasible solution to supplement the power of your home. In Japan, photovoltaics are competitive with other types of power. In america alone, new incentive programs make this form of solar technology ever more viable in many states. An increasingly popular and practical method of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.

5. Large independent photovoltaic systems. For those who have enough sun power at your site, you might be able to go off grid. It's also possible to integrate or hybridize your solar energy system with wind power or other kinds of sustainable energy to stay 'off the grid.'

How do Photovoltaic panels work ?

Silicon is mounted beneath non-reflective glass to create photovoltaic panels. These panels collect photons from the sun, converting them into DC electric power. The power created then flows into an inverter. The inverter transforms the energy into basic voltage and AC electric power.

Solar cells are prepared with particular materials called semiconductors like silicon, which is presently the most generally used. When light hits the Photovoltaic cell, a specific share of it is absorbed inside the semiconductor material. This means that the energy of the absorbed light is given to the semiconductor.

The energy unfastens the electrons, permitting them to run freely. Pv cells also have one or more electric fields that act to compel electrons unfastened by light absorption to flow in a specific direction. This flow of electrons is a current, and by introducing metal links on the top and bottom of the -Photovoltaic cell, the current can be drawn to use it externally.

What are the positives and negatives of solar energy ?

Solar Pro Arguments

- Heating our homes with oil or propane or using electricity from power plants running with fossil fuels is a reason behind climatic change and climate disruption. Solar power, on the other hand, is clean and environmentally-friendly.

- Solar hot-water heaters require little maintenance, and their initial investment can be recovered within a relatively small amount of time.

- Solar hot-water heaters can work in almost any climate, even just in very cold ones. Simply choose the right system for your climate: drainback, thermosyphon, batch-ICS, etc.

- Maintenance costs of solar powered systems are minimal and the warranties large.

- Financial incentives (USA, Canada, European states…) can reduce the cost of the initial investment in solar technologies. The U.S. government, for example, offers tax credits for solar systems certified by by the SRCC (Solar Rating and Certification Corporation), which amount to 30 percent of the investment (2009-2016 period).

Solar Cons Arguments

- The initial investment in Solar Water heaters or in Photovoltaic Electric Systems is greater than that required by conventional electric and gas heaters systems.

- The payback period of solar PV-electric systems is high, as well as those of solar space heating or solar cooling (only the solar domestic hot water heating payback is short or relatively short).

- Solar water heating do not support a direct in conjunction with radiators (including baseboard ones).

- Some air cooling (solar space heating and the solar cooling systems) are very pricey, and rather untested technologies: solar air-con isn't, till now, a truly economical option.

- The efficiency of solar powered systems is rather dependent on sunlight resources. It's in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.

Who am i ? - Barbara Young writes on solar RV panels in her personal hobby website 12voltsolarpanels.net. Her efforts are dedicated to helping people save energy using solar power to lower CO2 emissions and energy dependency.

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In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.